Data processors are typically designed to meet specific product needs. For example, desktop microprocessors operate at very high speeds and have long execution pipelines and multiple parallel resources to achieve very high performance. Microprocessors for laptop computers offer reasonably high performance but have low power features to lengthen battery life. Embedded microprocessors operate at relatively slow speeds and have simple architectures in order to reduce product cost.
Certain products such as multimedia mobile devices can at various times require either high performance or low power consumption. For example when running certain games, a multimedia mobile device requires the microprocessor to provide high performance. However when running other tasks such as EMAIL, the multimedia mobile device requires much lower performance from the microprocessor. These varying processing environments make it difficult for the microprocessor designer to achieve the right balance between performance and preservation of battery life.
In the following description, the use of the same reference numerals in different drawings indicates similar or identical items. Unless otherwise noted, the word “coupled” and its associated verb forms include both direct connection and indirect electrical connection by means known in the art, and unless otherwise noted any description of direct connection implies alternate embodiments using suitable forms of indirect electrical connection as well.